COMPARISON STUDY OF ANTIOXIDANT, ANTIMICROBIAL AND CYTOTOXIC PROPERTIES OF SECONDARY METABOLITE AND PROTEIN EXTRACTS FROM CLINACANTHUS NUTANS

Abstract

Objective: The present study aims to evaluate the antioxidant, antimicrobial and cytotoxic properties of the secondary metabolites and proteins extracted from Clinacanthus nutans. Methods: Methanol (ME) and acetone (AC) and also protein (PE) extracts were obtained from Clinacanthus nutans. Antioxidant activity of sample extracts was examined by using 1,1-Diphenyl-2-Picrydyl Hydrazyl (DPPH) assay and antimicrobial activity was examined by using the agar diffusion method against Bacillus subtilis, Bacillus cereus, Streptococcus pyrogenes, Escherichia coli, and Pseudomonas aeroginosa bacterial strain. The cytotoxic potential was determined by brine shrimp lethality assay. Results: Methanol extract (ME) demonstrated to have the highest antioxidant activity with IC50 value of 98.84 μg/ml, followed by acetone extract (AE) with IC50 value of 134.83µg/ml, and protein extract (PE) with IC50 value of 353.49 µg/ml. Among all of the sample extracts, only methanol crude extracts (ME) displayed moderate inhibition against Gram-positive B. cereus (7.33±1.15 mm) and S. pyrogenes (8.67±0.57 mm) at concentration of 100 mg/ml, while both acetone (AE) and protein (PE) extracts had no activity against all tested microorganisms. All extracts from methanol (ME), acetone (AE) and protein (PE) exhibited significant cytotoxic activity against brine shrimps at LC50 7.2 μg/ml, 1.42 μg/ml and 70.6 μg/ml respectively. Conclusion: These data proved that methanol extract from the leaves of Clinacanthus nutans is the most potent among all samples tested and has the potential to be developed as an antioxidant, antimicrobial and cytotoxic agents. Whilst, acetone and protein crude extracts have potent antioxidant and cytotoxicity activities.